Keep an eye out at Handicraft Market — you're likely to discover some treasure or funny trinket among the stalls here. After you've admired the wares, enjoy a meal from one of the food vendors.
This Tula de Allende community marketplace is a good place to start your day of sightseeing. There's loads to discover nearby, such as Tula Archaeological Site, Tula National Park, and Quetzalcoatl Historical Room. Take your time at Handicraft Market before hitting up these other fine attractions.